1. Field of the Invention
The present invention relates to a blind riveting device for placing blind rivets, the blind riveting device including a device head, wherein an opening for receiving a rivet bolt and a suction device for producing a negative pressure which holds the rivet bolt in the opening are arranged in the head, and a control unit for switching the suction device on and off by means of an actuating element at a handle which is connected to the head.
2. Description of the Related Art
A blind riveting device of this type is disclosed in EP 1 013 358 A2. In this known blind riveting device, a control bolt is arranged at the handle, wherein the control bolt can be pressed in by means of the middle finger in order to activate the suction device. A lever may additionally be arranged at the control bolt, such that the suction device can be actuated with the lower three fingers of a hand, i.e., the middle finger, the ring finger and the little finger, when the blind riveting device is picked up for placing rivets. When the suction device has been actuated, the negative pressure holds a rivet bolt of a blind rivet which has been inserted into the mouth piece of the blind riveting device, so that the blind rivet does not fall out, even when the blind riveting device is directed downwardly. When the handle of the blind riveting device is released, the suction device is once again switched off, so that an unnecessary consumption of air can be avoided.
However, this known blind riveting device has the disadvantage that the work cannot always be performed with the required safety and reliability during longer use. The compressed air required for producing the negative pressure is only switched on when the blind riveting device is picked up. However, holding the blind riveting device always in a hand in the required position in such a way that the suction device is switched on or remains activated is relatively cumbersome and requires continuous concentration. It is absolutely required for a problem-free operation of the blind riveting device that always at least one finger presses the control bolt or the lever mounted on the control bolt. This results in a compulsory holding position of the fingers at the handle of the blind riveting device which does not make it possible to work without fatigue and which may frequently result in problems of the operation of the blind riveting device when the handle is held in an unconcentrated manner. The resulting problems are either that the blind rivet drops out during the riveting procedures when the mouth piece is directed downwardly, or that the residual bolt is not suctioned away after the riveting procedure has been concluded. Since a blind riveting device of this type is usually used for assembly operations in which two or more components are to be riveted together, the operator must align the components relative to each other in such a way that the bores which are intended for receiving the blind rivets coincide. During such a manipulation of the components there is the danger that the operator changes his holding position of the handle in such a way that the suction device is no longer active and is inadvertently inoperative. In that case, a blind rivet inserted into the opening of the mouthpiece may drop out. This makes it not only necessary to reinsert a new blind rivet, but the blind rivet which has dropped out may lead to a substantial interruption of the further assembly operation. If the residual bolt is not suctioned away into the collecting container after riveting, the rivet drops out toward the front, which leads to an interruption of the work rhythm or may result in clogging within the duct for the removal of the residual bolt.